Meiolania had an unusually shaped skull that sported many knob-like and horn-like protrusions. Two large horns faced sideways, giving the skull a total width of 60 centimetres (2.0 ft), and would have prevented the animal fully withdrawing its head into its shell. The tail was protected by armored 'rings', and sported thorn-like spikes at the end.[3] The body form of Meiolania may be viewed as having converged towards those of dinosaurian ankylosaurids and xenarthran glyptodonts.

The genus was erected in 1886 based on remains found on Lord Howe Island, which Richard Owen assigned to the two species M. platyceps and M. minor (now a synonym of the latter).[4] These were the first good meiolaniid remains, and were used to show that the first known remains of a related animal, a species from Queensland now known as Ninjemys oweni (which was assigned to Meiolania until 1992), did not belong to lizards as initially thought, but to turtles.[5] Woodward sank Niolamia argentina into Meiolania, but this was not accepted by later authors.

It is thought that M. damelipi was hunted to extinction by the Lapita people about 3,000 years ago, based on the presence of bones at the bottom of a garbage midden at an archeological site.[7][9] The remains were primarily leg bones, indicating the turtles were butchered elsewhere.[7] The bones were not present in younger layers of the mound, suggesting the turtles disappeared within 300 years of first human contact.[7][9]